Answer:
if repetition is allowed,
if repetition is not allowed.
Step-by-step explanation:
For the first case, we have a choice of 26 letters <em>each step of the way. </em>For each of the 26 letters we can pick for the first slot, we can pick 26 for the second, and for each of <em>those</em> 26, we can pick between 26 again for our third slot, and well, you get the idea. Each step, we're multiplying the number of possible passwords by 26, so for a four-letter password, that comes out to 26 × 26 × 26 × 26 =
possible passwords.
If repetition is <em>not </em>allowed, we're slowly going to deplete our supply of letters. We still get 26 to choose from for the first letter, but once we've picked it, we only have 25 for the second. Once we pick the second, we only have 24 for the third, and so on for the fourth. This gives us instead a pretty generous choice of 26 × 25 × 24 × 23 passwords.
Answer:
The average rate of change of the function over the interval is of 6.
Step-by-step explanation:
Average rate of change:
The average rate of change of a function h(x) over an interval [a,b] is given by:

In this question:
Over the interval [-9,-2], so 
The function is:



Then

The average rate of change of the function over the interval is of 6.
Take 3 out of both of them
3(5x+2)
Since the operation between the two sets of parentheses is addition, we don't have to do anything with it, and can remove the parentheses.
Our new expression is: 2y^2+9y+4-3y^2-3y-9
Now, we just add like terms together to solve for the simplest form of the expression.
2y^2+9y+4-3y^2-3y-9
(2-3)y^2+(9-3)y+(4-9)
-y^2+6y-5
Our final answer is -y^2+6y-5.
The number of points Marco needs to bring his average up to 90% is 15points.
If there's a possible 25 possible points, and Marco has taken 5 quizzes;
Evidently, each quiz has weighs 5 points.
Mathematically;

- 2100 + 500x = 2250 + 450x
x = 3.
Therefore, he needs 5x points = 15 points to bring his average up to 90%.
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